This invention involves fluid control ball or plug valves and valve stem extensions to allow the valve to be turned free of obstructions located close to the valve body.
Fluid control valves continue to be the most troublesome of continuing maintenance and performance problems in any systems utilizing fluid flow. For example, most of the maintenance problems in a chemical manufacturing plant or a power plant involve valves in some way or the other. With emphasis on energy conservation, it is now standard practice to insulate most piping systems which are running above or below ambient temperatures. When the insulation is extended to cover the valve body, special arrangements must be made. It is not usually practical to cover up the handle or the wheel used to turn the valve stem to open or close the valve. Valve extensions have been provided in various configurations to extend the handle or wheel to a position outside of the insulation so that the valve can be opened or closed without disputing the insulation covering.
This invention is directed to ball or plug valves, wherein a one-quarter turn of the wheel or handle changes the flow from full "on" to full "off" in that direction. The valves may be two way, three way or even four way valves. The two way valves have a single flow bore through the ball or plug, while the three way have a "T" shaped bore to provide a third path.
Prior stem extensions such as those supplied by Jamesbury Corporation, of Worcester, Massachusetts and by Watts Regulator Industrial Products Company of Lawrence, Massachusetts and extensions described in U.S. Pat. Nos. 3,582,116 to Steven A. Young and 905,172 to R. S. Goodson illustrate extensions that utilize bolts and attachment mechanisms that do not provide convenience combined with the necessary durability for industrial use. The loosening of disengagement of a valve extension even after months or years of operation causes a severe safety hazard particularly when high temperature fluids or toxic chemicals are passing through the valve system. A typical Jamesbury extension is welded into place and cannot removed on line.
An additional problem involves the necessity of locking the valves in position, either in an open position or in the closed position. Again, because of safety considerations, such as when maintenance is being undertaken on the line, it is typically absolutely necessary to prevent unauthorized changing of the valve closure position. A number of locking mechanisms are provided in the industry to prevent unauthorized opening or closing of control valves, but the use of insulation on the pipes with a valve stem extension poses problems and needs not satisfied by these prior devices. It is necessary to provide a locking mechanism wherein the valve handle may be locked in either an open or a closed position without disrupting the insulation when the valve closure is to be changed. Further, it is important that water and other fluids cannot penetrate along the valve stem extension into and under the insulation to cause corrosion or other maintenance problems for the valve and the insulation covering.
None of the prior art devices satisfy these needs or attain the objects described herein below.